com.unity.uiwidgets/Samples/UIWidgetsGallery/demo/material/buttons_demo.cs

using System;
using System.Collections.Generic;
using System.Linq;
using Unity.UIWidgets.foundation;
using Unity.UIWidgets.material;
using Unity.UIWidgets.painting;
using Unity.UIWidgets.rendering;
using Unity.UIWidgets.widgets;

namespace UIWidgetsGallery.gallery {

class ButtonsDemo : StatefulWidget {
  public const String routeName = "/material/buttons";

  public ButtonsDemo(Key key = null) : base(key: key) {
      
  }

  public override State createState() => new _ButtonsDemoState();
}

class _ButtonsDemoState : State<ButtonsDemo> {
    const String _raisedText =
        "Raised buttons add dimension to mostly flat layouts. They emphasize " +
            "functions on busy or wide spaces.";

    const String _raisedCode = "buttons_raised";

    const String _flatText = "A flat button displays an ink splash on press " +
        "but does not lift. Use flat buttons on toolbars, in dialogs and " +
        "inline with padding";

    const String _flatCode = "buttons_flat";

    const String _outlineText =
        "Outline buttons become opaque and elevate when pressed. They are often " +
            "paired with raised buttons to indicate an alternative, secondary action.";

    const String _outlineCode = "buttons_outline";

    const String _dropdownText =
        "A dropdown button displays a menu that's used to select a value from a " +
            "small set of values. The button displays the current value and a down " +
            "arrow.";

    const String _dropdownCode = "buttons_dropdown";

    const String _iconText =
        "IconButtons are appropriate for toggle buttons that allow a single choice " +
            "to be selected or deselected, such as adding or removing an item's star.";

    const String _iconCode = "buttons_icon";

    const String _actionText =
        "Floating action buttons are used for a promoted action. They are " +
            "distinguished by a circled icon floating above the UI and can have motion " +
            "behaviors that include morphing, launching, and a transferring anchor " +
            "point.";

    const String _actionCode = "buttons_action";
    
  ShapeBorder _buttonShape;

  public _ButtonsDemoState() {
      
  }

  public override Widget build(BuildContext context) {
    ButtonThemeData buttonTheme = ButtonTheme.of(context).copyWith(
      shape: this._buttonShape
    );

    List<ComponentDemoTabData> demos = new List<ComponentDemoTabData>{
      new ComponentDemoTabData(
        tabName: "RAISED",
        description: _raisedText,
        demoWidget: ButtonTheme.fromButtonThemeData(
          data: buttonTheme,
          child: this.buildRaisedButton()
        ),
        exampleCodeTag: _raisedCode,
        documentationUrl: "https://docs.flutter.io/flutter/material/RaisedButton-class.html"
      ),
      new ComponentDemoTabData(
        tabName: "FLAT",
        description: _flatText,
        demoWidget: ButtonTheme.fromButtonThemeData(
          data: buttonTheme,
          child: this.buildFlatButton()
        ),
        exampleCodeTag: _flatCode,
        documentationUrl: "https://docs.flutter.io/flutter/material/FlatButton-class.html"
      ),
      new ComponentDemoTabData(
        tabName: "OUTLINE",
        description: _outlineText,
        demoWidget: ButtonTheme.fromButtonThemeData(
          data: buttonTheme,
          child: this.buildOutlineButton()
        ),
        exampleCodeTag: _outlineCode,
        documentationUrl: "https://docs.flutter.io/flutter/material/OutlineButton-class.html"
      ),
      new ComponentDemoTabData(
        tabName: "DROPDOWN",
        description: _dropdownText,
        demoWidget: this.buildDropdownButton(),
        exampleCodeTag: _dropdownCode,
        documentationUrl: "https://docs.flutter.io/flutter/material/DropdownButton-class.html"
      ),
      new ComponentDemoTabData(
        tabName: "ICON",
        description: _iconText,
        demoWidget: this.buildIconButton(),
        exampleCodeTag: _iconCode,
        documentationUrl: "https://docs.flutter.io/flutter/material/IconButton-class.html"
      ),
      new ComponentDemoTabData(
        tabName: "ACTION",
        description: _actionText,
        demoWidget: this.buildActionButton(),
        exampleCodeTag: _actionCode,
        documentationUrl: "https://docs.flutter.io/flutter/material/FloatingActionButton-class.html"
      )
    };

    return new TabbedComponentDemoScaffold(
      title: "Buttons",
      demos: demos,
      actions: new List<Widget>{
        new IconButton(
          icon: new Icon(Icons.sentiment_very_satisfied),
          onPressed: () => {
            this.setState(() => {
              this._buttonShape = this._buttonShape == null ? new StadiumBorder() : null;
            });
          }
        )
      }
    );
          
          
}
  
  public Widget buildRaisedButton() {
    return new Align(
      alignment: new Alignment(0.0f, -0.2f),
      child: new Column(
        mainAxisSize: MainAxisSize.min,
        children: new List<Widget>{
          new ButtonBar(
            mainAxisSize: MainAxisSize.min,
            children: new List<Widget>{
              new RaisedButton(
                child: new Text("RAISED BUTTON"),
                onPressed: () => {
                  // Perform some action
                }
              ),
              new RaisedButton(
                child: new Text("DISABLED"),
                onPressed: null
              )
            }
          ),
          new ButtonBar(
            mainAxisSize: MainAxisSize.min,
            children: new List<Widget>{
              RaisedButton.icon(
                icon: new Icon(Icons.add, size: 18.0f),
                label: new Text("RAISED BUTTON"),
                onPressed: () => {
                  // Perform some action
                }
              ),
              RaisedButton.icon(
                icon: new Icon(Icons.add, size: 18.0f),
                label: new Text("DISABLED"),
                onPressed: null
              )
            }
          )
        }
      )
    );
  }

  public Widget buildFlatButton() {
      return new Align(
          alignment: new Alignment(0.0f, -0.2f),
          child: new Column(
              mainAxisSize: MainAxisSize.min,
              children: new List<Widget> {
                new ButtonBar(
                    mainAxisSize: MainAxisSize.min,
                    children: new List< Widget >{
                        new FlatButton(
                            child: new Text ("FLAT BUTTON"),
                            onPressed: () => {
                              // Perform some action
                            }
                        ),
                        new FlatButton (
                            child: new Text("DISABLED"),
                            onPressed: null
                        )
                    }
                ),
                  new ButtonBar(
                      mainAxisSize: MainAxisSize.min,
                      children: new List<Widget>{
                          FlatButton.icon(
                            icon: new Icon(Icons.add_circle_outline, size: 18.0f),
                            label: new Text ("FLAT BUTTON"),
                            onPressed: () => {
                                  // Perform some action
                            }
                          ),
                          FlatButton.icon(
                            icon: new Icon (Icons.add_circle_outline, size: 18.0f),
                            label: new Text ("DISABLED"),
                                onPressed: null
                          ),
                      }
                  )
                }
            )
      );
    }

  Widget buildOutlineButton() {
      return new Align(
          alignment: new Alignment (0.0f, -0.2f),
          child: new Column(
            mainAxisSize: MainAxisSize.min,
            children: new List<Widget> {
              new ButtonBar(
                  mainAxisSize: MainAxisSize.min,
                  children: new List<Widget> {
                      new OutlineButton(
                          child: new Text("OUTLINE BUTTON"),
                          onPressed: () => {
                              // Perform some action
                          }
                      ),
 
                      new OutlineButton(
                        child: new Text("DISABLED"),
                        onPressed: null
                      )
                  }
              ),
              new ButtonBar(
                  mainAxisSize: MainAxisSize.min,
                  children: new List<Widget> {
                      OutlineButton.icon(
                          icon: new Icon(Icons.add, size: 18.0f),
                          label: new Text("OUTLINE BUTTON"),
                          onPressed: () => {
                          // Perform some action
                        }
                      ),
                      OutlineButton.icon(
                          icon: new Icon(Icons.add, size: 18.0f),
                          label: new Text("DISABLED"),
                          onPressed: null
                      )
                  }
              )
            }
          )
      );
  }

      // https://en.wikipedia.org/wiki/Free_Four
      string dropdown1Value = "Free";
      string dropdown2Value;
      string dropdown3Value = "Four";

      public Widget buildDropdownButton() {
          return new Padding(
              padding: EdgeInsets.all(24.0f),
              child: new Column(
                  mainAxisAlignment: MainAxisAlignment.start,
                  children: new List<Widget> {
                    new ListTile(
                        title: new Text ("Simple dropdown:"),
                        trailing: new DropdownButton<string>(
                            value: this.dropdown1Value,
                            onChanged: (string newValue) => {
                                this.setState(() => {
                                    this.dropdown1Value = newValue;
                                });
                            },
                            items: new List<string> {"One", "Two", "Free", "Four"}.Select((string value) => {
                                return new DropdownMenuItem<string>(
                                    value: value,
                                    child: new Text(value)
                                );
                            }).ToList()
                        )
                    ),
                    new SizedBox (
                        height: 24.0f
                    ),
                    new ListTile(
                        title: new Text ("Dropdown with a hint:"),
                        trailing: new DropdownButton<string>(
                            value: this.dropdown2Value,
                            hint: new Text ("Choose"),
                            onChanged: (string newValue) => {
                                this.setState(() => {
                                    this.dropdown2Value = newValue;
                                });
                            },
                            items: new List<String >{"One", "Two", "Free", "Four"}.Select((string value) => {
                                return new DropdownMenuItem<string>(
                                    value: value,
                                    child: new Text(value)
                                );
                            }).ToList()
                        )
                    ),
                    new SizedBox (
                        height: 24.0f
                    ),
                    new ListTile(
                        title: new Text ("Scrollable dropdown:"),
                        trailing: new DropdownButton<string>(
                            value: this.dropdown3Value,
                            onChanged: (string newValue) => {
                                this.setState(() => {
                                    this.dropdown3Value = newValue;
                                });
                            },
                            items: new List <String >{
                                "One", "Two", "Free", "Four", "Can", "I", "Have", "A", "Little",
                                "Bit", "More", "Five", "Six", "Seven", "Eight", "Nine", "Ten"
                            }.Select<string, DropdownMenuItem<string>>(value => {
                                return new DropdownMenuItem<string>(
                                    value: value,
                                    child: new Text(value)
                                );
                            }).ToList()
                        )
                    )
                  }
                )
          );
      }

      bool iconButtonToggle = false;

      public Widget buildIconButton() {
          return new Align(
              alignment: new Alignment (0.0f, -0.2f),
              child: new Row(
                  mainAxisSize: MainAxisSize.min,
                  children: new List< Widget >{
                      new IconButton(
                          icon: new Icon (
                            Icons.thumb_up
                          ),
                          onPressed: () => { this.setState(() => this.iconButtonToggle = !this.iconButtonToggle); },
                          color: this.iconButtonToggle ? Theme.of(this.context).primaryColor : null
                      ),
                      new IconButton(
                          icon: new Icon(
                              Icons.thumb_up
                          ),
                          onPressed: null
                      )
                  }.Select<Widget, Widget>((Widget button) => new SizedBox(width: 64.0f, height: 64.0f, child: button)).ToList()
              )
          );
      }

      public Widget buildActionButton() {
          return new Align(
              alignment: new Alignment (0.0f, -0.2f),
              child: new FloatingActionButton(
                  child: new Icon(Icons.add),
                  onPressed: () => {
                      // Perform some action
                  },
                  tooltip: "floating action button"
              )
          );
      }
  }
}